Being made in the 15th week of 1991, this is an early 486DX33. In that time-frame the 386 at 25MHz or 33MHz was considered a modern PC. 286 was already low-end and the 486 was high-end. Note that the 486 logo is missing the DX suffix because there was no 486SX made yet. The first SX CPUs started app... > Read more

20MHz; one of the slowest 486 chips available (there are 16MHz parts as well). Thankfully it didn't sell well because it is quite a lot slower than the SX25. It's only a difference of 5MHz but remember that the front-side-bus (FSB) is also 5MHz slower. This will cause the impact to be bigger.... > Read more

Same as this SX 25 but with a different sSpec number and that it's more than two years older.... > Read more

A KU80486SX-25 (in QFP package) fitted on an UMC 4SLUD motherboard from 1992. ... > Read more

Exactly the same as the SX33 except for the integrated co-processor. This co-processor is used for floating point calculations. At the time normal applications didn't use the FPU (floating point unit) so people had enough power with only the, much cheaper, SX 33MHz processor. After all Doom ran just... > Read more

I bought this CPU in a package deal along with a few other CPU's. Amazingly enough this CPU has the same sSpec number and production date as my other sSpec SX419 DX33. What are the odds .... > Read more

A 1992 486DX-50; a good performer back in '92 but with high FSB which could be troublesome. The DX2/50 which runs at 25MHz FSB (clock-doubled) won't give you trouble but due the slower bus speed it will be slower with games or I/O.... > Read more

Both the Am486DX40 and Cx486DX40 were tricky on early motherboards because of their high bus speed. Think again and look at this 50MHz part that requires a 50MHz front side bus. 50MHz sounds like it will fly but unfortunately it doesn't.

My UMC PCI motherboard automatically sets the PCI bus on 25... > Read more

The same as the 80486SX2/50 but with floating point unit (FPU) on-board. The FPU is used for floating point calculations and comes in to play with CAD and Excel. Back then games didn't really use it yet so Doom will run pretty much the same on a SX2. Quake d... > Read more

A regular 486DX33. Although not many people used the 'DX' part (which indicates it has an on-board co-processor) a lot of people thought that the 'DX' was faster. They would've been right if it was a 386 because the SX/DX suffix has a different meaning with 386's. With 386 class processors SX means ... > Read more

A regular Intel 486DX2/50 that runs at 50MHz using a 25MHz FSB. It does it's job but if you could overclock this to 66MHz you could gain, in a VLB or PCI configuration, 25% more speed in Doom due to both the higher CPU clock and higher front-side-bus .

If memory serves me correctly this CPU was... > Read more

The DX2/66 was a popular processor in the 486 era. It has enough oomph to run Windows 3.1 and DOS-games from that era. For instance: Doom runs a lot smoother on a system with a DX2/66 fitted instead of a DX33, especially when you're running a Vesa Local BUS (VLB) graphics card.

This partic... > Read more

.... > Read more

.... > Read more

An unusual processor. Most people either bought the SX33, DX33 or went for the DX2/66MHz. The DX2/66MHz usually gave the extra oomph compared to the 50MHz part and was worth the extra cash.

The SX2 doesn't have an integrated floating point unit (FPU) like any other 486SX CPU. Besides that it is e... > Read more

A 25MHz 80486 SX processor. Not very fast but it's not the slowest 486 ever made. This one runs 5MHz faster which is noticeably in applications. The SX25 could be overclocked to 33MHz quite often without any hassle. 8MHz may not sound much but will greatly improve the speed of the system. Especially... > Read more

i486DX2/50 CPU in QFP package mounted on a Compaq CPU board for Compaq notebooks from 1994.... > Read more

.... > Read more

The SX33 was quite a good processor for a while. Both AMD and Cyrix made 33MHz parts as well but DX/2, DX/4 and even DX/5 parts from these companies can be found more easily. This is because AMD and Cyrix had to make their own 486 because Intel didn't gave the 'howto make a 486-manual' to AMD and Cy... > Read more

Made in week 28 of 1994 which makes it a somewhat late 486 DX2/50. In that time-frame the Pentium 90 was Intel's flagship and running a DX/2 66MHz, DX/2 80 or even DX/4 100MHz made more sense in 1994. However, these 50MHz parts usually run fine at 66MHz and this particular example even booted up at ... > Read more

This is not the first 66MHz CPU in my database. In fact it's the third Intel 486DX2/66. The other two have a different sSpec number and one of them is faster than usual because it has write-back cache.... > Read more

The first 100MHz ticking part Intel brought onto the x86 market. The DX4/100 was actually a DX3/100 as it didn't clock quadruple but clock triple the front side bus frequency.

In many cases an old 486 couldn't be upgraded to the DX4/100. Not only because some motherboards didn't understand the cl... > Read more

Unlike this 486DX2/66 it has no build on heatsink. This allowed people to stick their own heatsink/fan solution onto it as the 486DX2/66 didn't run happy without heatsink.

This version of the DX2/66 is the fastest Intel ever made. See the benchmarks where... > Read more

.... > Read more

A late DX2/66 (40th week of 1996). In late '96 486 at 100, 120 or 133MHz were considered low-end and Pentium's at 100 or 133MHz were commonplace with 166MHz being the top model.

An interesting twitch of this CPU is the indication of the model number. Every 486 has an indication of it's type and s... > Read more